There is a new gimmick in gas price warefare. I see the western states have de-rated regular gas from 87 octane to 85 or 85.5 octane for the same price. The usual 87 octane is now called "blended" or "plus" or such and costs around 10 cents a gallon more (and "premium" yet another 10 cents more).

In flat land that probably does not cause a problem because low octane pinging can be controlled by the engine computer. I got fooled the first fill-up. Power was effected. I had a struggle to pull the 11,000 feet of the Chief Joseph and Beartooth highways near Cody, WY. I now pay the extra price.

I understand that the higher the octane rating, the slower the fuel burns. The lower the rating, the faster the fuel burns. Performance cars with higher compression engines require high octane to burn slower to prevent pre-detination we all know as the bottle rattling noise or pinging.

When driving in high altitude 5000 feet and higher, the oxygen in the air is thinner. The fuel is formulated accordingly with less octane for the fuel to burn better with less oxygen. So there is a logic to the lower octane at high altitude. It is not a gimmick. It has been that way for as long as I can remember.

BUT.......

In the case with our Ford V10 gasoline engines, the owners manual says to maintain 87 octane even in high altitude conditions. In my 2007 owners manual it is stated so on page 228 under "Octane Recommendations". This coincides with your experience. It also says that your engine sometimes will ping lightly which is considered normal. Excessive pinging is cause to see a mechanic.

So your advise is "Right On". Pay the money and always use 87 octane fuel.

On a related note, never use a higher rated octane than your engine requires. This because over time, carbon (black soot) will build up on the valve seats which in turn causes pinging. It's sort-of-like getting your engine addicted/dependant on high octane fuel. So if you have consistently run premium fuel in a regular octane engine and suddenly switch to regular fuel as stated in the owners manual, the engine could ping a lot, forcing you to return to premium fuel.

There are decarbonizing products on the market which can sometimes be effective in fixing the addiction, pending the severity of the carbon build-up. Generally speaking fuel additives are less effective than the type that gets sucked in through a vacuum line off the intake manifold. I had very good luck with OTC D-Karbonizer on a Pontiac Fiero-GT I once treasured. I bought the car used and it pinged unless I used premium fuel. After the treatment, I was able to use regular gas as the owners manual says to. The engine seemed to have a bit more power, and of coarse my fuel costs were lower.

The OTC D-Karbonizer is a pint sized bottle of special liquid that you allow the intake vacuum draw in the liquid over the coarse of a minute or so, per instructions. When the fluid is all drawn in, you quickly turn off the engine and allow the liquid to soak into the carbon soot on the valves for a certain amount of time. Then drive the vehicle for so many miles. The D-Karbonizer liquid loosens up the soot and driving the vehicle cleans it off quickly. It's sort of a crazy process because when the fluid is drawn in, the engine wants to die so you need someone in the driver seat with the gas pedal to maintain a certian engine rpm. During this time, the exhaust billows out white smoke. It's scary but it works. Safe for catalytic converters, sensors and all.

« Last Edit: July 02, 2013, 11:52:55 am by ron.dittmer »

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Ron Dittmer (wife Irene) 2007 Model 2350 Without A SlideoutOur Rig Is Available For Viewing Any Time Of Year In Dundee, ILStored At Home In Our Heated Garage (Well-Lit & Warm Comfort In Winter)

Excellent points to remember,,, I think we had a thread on gas pricing earlier,, Gas buddy breaks down the different octanes, but only gives reg, mid, high when looking at the station,, looked quickly, but like Ron says,,, you never go wrong with 87 did not see any with the actual number listed What about the alcohol level??/ I know we are OK with the 10% or less,,, David Sparks2008 PC 2350Houston

I think the E85 gas you see for sale in limited fashion is 85% ethanol /alcohol. It is not good for conventional vehicles though I would think one tank full purchased by accident, burned in a day won't do harm. The vehicle needs to be approved by the manufacture to use this type of fuel. Your vehicle owners manual is the place to get the answer.

All normal fuel can have as much as 10% alcohol without concern for your vehicle. For the PC Ford E350/E450, stay with 87 octane with no more than 10% ethanol and you can't go wrong.

I wonder if you bought cheaper fuel, it might negatively affect your PC's fuel economy such that it would cost you more anyway.

« Last Edit: July 03, 2013, 10:13:10 am by ron.dittmer »

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Ron Dittmer (wife Irene) 2007 Model 2350 Without A SlideoutOur Rig Is Available For Viewing Any Time Of Year In Dundee, ILStored At Home In Our Heated Garage (Well-Lit & Warm Comfort In Winter)

My car/truck books for an Audi and a Murano and a Frontier say that the computer cannot deal with E85 and probably will not run on it. Two of them say not to try it and drain it. All three are adamantly against E15 too.

Just for info the "greens" were not the ones against MTBE and substituting grain produced ethanol - can you guess who was for it? Or who is leading the surge for E15?